tools/xen-foreign: Update the size for vcpu_guest_{core_regs, context}

Commit 918b8842a8 ("arm64: Change type of hsr, cpsr, spsr_el1 to
uint64_t") updated the size of the structure vcpu_guest_core_regs and
indirectly vcpu_guest_context.

On Arm, the two structures are only accessible to the tools and the
hypervisor (and therefore stable). However, they are still checked
by the scripts in tools/include/xen-foreign are not able to understand
that.

Ideally we should rework the scripts so we don't have to update
the size for non-stable structure. But I don't have limited time
to spend on the issue. So chose the simple solution and update
the size accordingly.

Note that we need to keep vcpu_guest_core_regs around because
the structure is used by vcpu_guest_context and therefore the
scripts expects the generated header to contain it.

Fixes: 918b8842a8 ("arm64: Change type of hsr, cpsr, spsr_el1 to uint64_t")
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Michal Orzel <michal.orzel@arm.com>
Tested-by: Michal Orzel <michal.orzel@arm.com>

tools/include/xen-foreign/reference.size

@@ -4,8 +4,8 @@ structs                   |   arm32   arm64  x86_32  x86_64
 start_info                |       -       -    1112    1168
 trap_info                 |       -       -       8      16
 cpu_user_regs             |       -       -      68     200
-vcpu_guest_core_regs      |     304     304       -       -
-vcpu_guest_context        |     344     344    2800    5168
+vcpu_guest_core_regs      |     312     312       -       -
+vcpu_guest_context        |     352     352    2800    5168
 arch_vcpu_info            |       0       0      24      16
 vcpu_time_info            |      32      32      32      32
 vcpu_info                 |      48      48      64      64